/*
 * Copyright (c) 2001-2008 Caucho Technology, Inc.  All rights reserved.
 *
 * The Apache Software License, Version 1.1
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Caucho Technology (http://www.caucho.com/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "Burlap", "Resin", and "Caucho" must not be used to
 *    endorse or promote products derived from this software without prior
 *    written permission. For written permission, please contact
 *    info@caucho.com.
 *
 * 5. Products derived from this software may not be called "Resin"
 *    nor may "Resin" appear in their names without prior written
 *    permission of Caucho Technology.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL CAUCHO TECHNOLOGY OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * @author Scott Ferguson
 */

package com.caucho.hessian.io;

import java.io.IOException;
import java.io.InputStream;

import java.util.logging.*;

/**
 * Input stream for Hessian 2 streaming requests using WebSocket.
 * 
 * For best performance, use HessianFactory:
 * 
 * <code><pre>
 * HessianFactory factory = new HessianFactory();
 * Hessian2StreamingInput hIn = factory.createHessian2StreamingInput(is);
 * </pre></code>
 */
public class Hessian2StreamingInput {
	private static final Logger log = Logger
			.getLogger(Hessian2StreamingInput.class.getName());

	private StreamingInputStream _is;
	private Hessian2Input _in;

	/**
	 * Creates a new Hessian input stream, initialized with an underlying input
	 * stream.
	 *
	 * @param is
	 *            the underlying output stream.
	 */
	public Hessian2StreamingInput(InputStream is) {
		_is = new StreamingInputStream(is);
		_in = new Hessian2Input(_is);
	}

	public void setSerializerFactory(SerializerFactory factory) {
		_in.setSerializerFactory(factory);
	}

	public boolean isDataAvailable() {
		StreamingInputStream is = _is;

		return is != null && is.isDataAvailable();
	}

	public Hessian2Input startPacket() throws IOException {
		if (_is.startPacket()) {
			_in.resetReferences();
			_in.resetBuffer(); // XXX:
			return _in;
		} else
			return null;
	}

	public void endPacket() throws IOException {
		_is.endPacket();
		_in.resetBuffer(); // XXX:
	}

	public Hessian2Input getHessianInput() {
		return _in;
	}

	/**
	 * Read the next object
	 */
	public Object readObject() throws IOException {
		_is.startPacket();

		Object obj = _in.readStreamingObject();

		_is.endPacket();

		return obj;
	}

	/**
	 * Close the output.
	 */
	public void close() throws IOException {
		_in.close();
	}

	static class StreamingInputStream extends InputStream {
		private InputStream _is;

		private int _length;
		private boolean _isPacketEnd;

		StreamingInputStream(InputStream is) {
			_is = is;
		}

		public boolean isDataAvailable() {
			try {
				return _is != null && _is.available() > 0;
			} catch (IOException e) {
				log.log(Level.FINER, e.toString(), e);

				return true;
			}
		}

		public boolean startPacket() throws IOException {
			// skip zero-length packets
			do {
				_isPacketEnd = false;
			} while ((_length = readChunkLength(_is)) == 0);

			return _length > 0;
		}

		public void endPacket() throws IOException {
			while (!_isPacketEnd) {
				if (_length <= 0)
					_length = readChunkLength(_is);

				if (_length > 0) {
					_is.skip(_length);
					_length = 0;
				}
			}

			if (_length > 0) {
				_is.skip(_length);
				_length = 0;
			}
		}

		public int read() throws IOException {
			InputStream is = _is;

			if (_length == 0) {
				if (_isPacketEnd)
					return -1;

				_length = readChunkLength(is);

				if (_length <= 0)
					return -1;
			}

			_length--;

			return is.read();
		}

		@Override
		public int read(byte[] buffer, int offset, int length) throws IOException {
			InputStream is = _is;

			if (_length <= 0) {
				if (_isPacketEnd)
					return -1;

				_length = readChunkLength(is);

				if (_length <= 0)
					return -1;
			}

			int sublen = _length;
			if (length < sublen)
				sublen = length;

			sublen = is.read(buffer, offset, sublen);

			if (sublen < 0)
				return -1;

			_length -= sublen;

			return sublen;
		}

		private int readChunkLength(InputStream is) throws IOException {
			if (_isPacketEnd)
				return -1;

			int length = 0;

			int code = is.read();

			if (code < 0) {
				_isPacketEnd = true;
				return -1;
			}

			_isPacketEnd = (code & 0x80) == 0;

			int len = is.read() & 0x7f;

			if (len < 0x7e) {
				length = len;
			} else if (len == 0x7e) {
				length = (((is.read() & 0xff) << 8) + (is.read() & 0xff));
			} else {
				length = (((is.read() & 0xff) << 56) + ((is.read() & 0xff) << 48)
						+ ((is.read() & 0xff) << 40) + ((is.read() & 0xff) << 32)
						+ ((is.read() & 0xff) << 24) + ((is.read() & 0xff) << 16)
						+ ((is.read() & 0xff) << 8) + ((is.read() & 0xff)));
			}

			return length;
		}
	}
}
